Co-incineration & Other Pre-treatment Options for Residual Waste
When a waste stream is combusted in an industrial or power plant as a substitute fuel, this is known as Co-incineration. This will still be subject to the requirements of the Waste Incineration Directive, although there has been discussion by the EA of relaxed regulatory regime for these processes. Examples of waste streams co-incinerated are Refuse Derived Fuels, waste tyres and secondary liquid fuels (oils, solvents). These may be combusted in Cement kilns or power stations. This has the advantage of being classified as 'recovery' by the European Commission and therefore will count towards recovery targets such as those within producer responsibility legislation.
Other Pre-treatment Options for Residual Waste
There are a variety of pre-treatment options for residual waste in order to facilitate stabilisation, homogenisation or separation. Indeed many of the waste treatments described are partially or primarily waste treatment processes prior to a further waste management application (e.g. RDF, MBT). Examples of other pre treatment systems available include:-
Steam reformation processes. These are where the wastes are subject to autoclaving or steam processing. This helps sanitise and reduce residual MSW to a 'flock' like material, with metals and glass partially cleaned for extraction as recyclables, but may melt plastics making these more difficult to recycle. The residual material may be thermally treated as a type of RDF.
Pulverisation / mechanical separation. Examples include Ball Mills where wastes are pulverised by the action of metal balls to facilitate later processing and separation into usable fractions (Leicester example). Other techniques include the use of Dano Drums which rotate and break down the waste mass. Pulverisation may also be used in RDF manufacture (see overleaf)
The following video show a hazardous waste incinerator during waste charging, the de-ashing system, and the wet flue gas treatment system etc.